a pure text file (although its extension is not TXT) is overwritten by unknown application on my windows7 64 bits. And I did not enable Previous Versions function.
So is there any tools, free if possible, which can search the hard-disk by given contents and export the text to a new TEXT file?
thanks
If it’s overwritten, simple answer is no, because the file contents would be corrupt. If it has just been accidentally deleted, you may be able to use Recuva, but I wouldn’t hold my breath.
Like colkai said: No.
And in addition to that, if some unknown app is starting to overwrite files that don’t belong to it, I really would like to know what is happening on my PC. Start running the basic virus scanner, trojan, rootkit & other infestation checking apps. Something could be messing with your data.
And always… Keep a backup (or 2) of your stuff! On external drives or the cloud. 
iBeesoft Data Recovery finds the WHOLE original file, yes I mean the file is overwritten but iBeesoft Data Recovery recovers every bytes from the beginning to the end. I don’t know how does iBeesoft Data Recovery work because before test I expect only part of the data can be found by reading the hard-disk sector in a very low speed way.
But iBeesoft Data Recovery is a commercial software which I can’t afford for treating one file( $45.95 is about the cost of my breakfast, lunch and dinner of 18 days), I have to take images then OCR
I’m very sorry to say that you should have been running backup software continuously.
For instance, on my Macintosh, everything is backed-up to an external disk drive at least once an hour, and I never look up to even notice that it is happening. (If I’ve just finished an important step, I call for the backup to occur immediately and wait for it to finish.) Microsoft, and several other companies, provides excellent backup software for Windows, but in that environment you must explicitly install and use it.
thanks. Since the file is actually pure text file, now I upload it to my privacy project on github